1. Field of the Invention
The invention relates generally to material or article handling and stacking apparatus, and more particularly to devices or apparatus for stacking sheet like items such as bank checks or similar documents in sequence of entry within document sorting pockets.
2. Description of the Prior Art
It is well-known in the document handling art to sort documents such as bank checks or data processing cards moving at high rates of speed by separating the same into a number of sorting pockets corresponding to various coding criteria. Document stacking apparatus located within each sorting pocket are coordinated with the flow of documents to stack the sheets on edge in sequence of entry within the preselected pockets.
Various means have been developed for stacking the sorted documents within pockets including cantilever springs, air jets, and the like, which kick the trailing end of each document as it passes into the pocket, imparting a sideward motion thereto for carrying the document onto a stationary stack. Examples of such stackers are illustrated by U.S. Pat. Nos. 3,628,788, 3,131,932 and 2,944,813 issued to W. L. Simmons, E. P. Maidment and J. G. Smith, respectively, and assigned to the same assignee as the present invention. While such stackers aid in preventing rear end collisons of the documents as they enter the pocket, their performance becomes limited by the passing clearance between the front edge of the incoming document and the tail end of the preceding document, and limited by the speed at which the documents are transported.
For example, the use of air jets requires spacing between documents to prevent the air jets from simultaneously pushing the tail end of one document and the front end of an incoming document, and also to permit sufficient flow of air to move the document into position. Whereas with the use of a kicker spring enough time should be allowed between consecutively entering documents for stacking the documents, due to the natural frequency-dependency characteristic of the spring.
Thus, the invention of a high speed stacking apparatus which is not limited by its slow response or natural frequency to stack documents is highly welcomed in the document handling art.